1. Field of the Invention
The present invention relates to a sheet for protecting a paint film from damage such as scratches and dirt.
This application claims priority from Japanese Patent Application No. 2008-316943, filed on Dec. 12, 2008, the entire contents of which are incorporated herein by reference.
2. Description of the Related Art
Technology is known for bonding a protective sheet to the paint film of articles having a paint film (e.g., painted automobiles and automotive components, sheet metal such as sheet steel and shaped articles thereof) in order to prevent damage to the paint film surface when, for example, transporting, storing, curing or constructing (sometimes collectively referred to below as “transporting, etc.”) the article. Paint film-protecting sheets used for such a purpose generally have a pressure-sensitive adhesive (PSA) layer on one side of a sheet-like substrate made of resin, and are constructed in such a way as to enable the aim of protection to be achieved by bonding of the sheet to the adherend surface (the paint film to be protected) via the PSA layer. This type of paint film-protecting sheet has been described in the prior-art, including Japanese Patent Application Publication Nos. H6-73352 and 2007-238746. In addition, Japanese Patent Application Publication No. 2005-213280 describes an anchoring agent composition for a PSA.
In recent years, the demand for greater decorativeness in the appearance of paint films has increased even further in efforts to increase the value of goods (automobiles, etc.). For example, when a paint film-protecting sheet whose protective role has come to an end is stripped (removed) from the surface of a paint film, there is a desire for a way to more reliably prevent deposits (typically some of the PSA making up the PSA layer) from the sheet from remaining behind on the surface of the paint film (a phenomenon known as “adhesive transfer”).
Conventional techniques for preventing adhesive transfer include a method wherein an ingredient which lowers adhesiveness is included in the PSA (Japanese Patent Application No. H6-73352), and a method for preventing deterioration of the PSA layer and suppressing adhesive transfer by using a substrate which includes a weathering stabilizer and has a specific ultraviolet light transmittance (Japanese Patent Application No. 2007-238746). Another conventional technique for preventing adhesive transfer is a method in which an anchoring agent is disposed between the substrate and the PSA (Japanese Patent Application Laid-open No. 2005-213280).